Tolerances and fit.

A couple of questions involving aircraft engines and in particular,
the K1A5 300 HP, IO540.

I've read a lot about blueprinting, but it seems to me that
blueprinting is not the same as optimizing.

How close are the Piston sets including rings, wrist pins and rods
balanced? How close would, or could you get on a custom balance job?

How close are the combustion chambers matched for volume?

How about the cross sectional area through the intake and exhaust
ports to the valve seats? Are they matched, smooth, and optimized for
flow?

Can all, or any of these be done/improved and the engine still remain
certified?

I would think that the piston sets could be balanced and remain
certified as long as they remained within spec. OTOH I have my doubts
about smoothing ports and combustion chamber volume matching.
GAMI injectors can be used to match fuel flows. Are they considered
stock items or do they take an STC?

I doubt that much is going to change in the way of combustion
efficiency, but OTOH I'd think that a very careful balance job,
combustion chamber matching, and polishing the ports would gain some
HP and result in a much smoother running engine.

Yes, I have a K1A5 IO540 that is going to get a rebuild. I just
haven't decided which way to go.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)